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Topic: intermitent exup fault,any ideas? (Read 4368 times)

Sorry folks,its another exup question.I have a gen1 1000 that has an intermitent exup fault that has started to appear at low revs while trundling through traffic,I stripped the valve and copper slipped everything,ajusted the cables,test rode the bike again and thought i had cured it,riding again in traffic yesterday the fault code on the tacho was displayed ,i turned the ignition off then on again and rode the bike for 30 miles or so and the fault is no longer displayed,the bike is mint has fsh and 33k miles.Any ideas?

I've just spent a couple of months faffing around with exactly the same thing.

The first thing I checked was that the valve was rotating freely and gave it a good lube and it was better but not fixed. So, I took it apart again, and again and it finally clicked that the damn spindle had a slight lip and the valve was sticking in the bushing.

So, I took a file to it and filed it back to profile, confident I'd nailed it . . you can guess . . a bit better but still not fixed. The rev counter now only flicked around for the first few miles.

And then it stopped altogether one day and for a couple of weeks all was fine. And then I started to notice that it sometimes wouldn't pull properly after coasting down from motorway speeds and getting away from the lights at low revs, it sometimes bogged.

So, I whipped the cover off and guess what, the return EXUP cable had snapped. This meant that it was ok going up the rev range where the valve opens, but it would take a lot of vibration and gravity to get it to return to closed for low revs. I suspect a snapped pull cable would be more obvious because in that case it wouldn't rev out properly.

So actually, it wasn't the valve at all, it was the cable getting progressively more sticky that was causing the original problem. Mind, after 102,000 miles, I don't blame them for getting past their due date. I've had to do both throttle cables recently and the clutch went 2 years ago.

So, after nearly passing out at the £150 quid price of a new pair of cables, I bought WeMoto's 'Slinky Glide' pattern cables and fitted them a couple of weeks ago. Worked like a charm. Fazer back on stun (sorry).

Anyway, final point - check the cables are running freely. It might not be the valve at all...

They are annoyingly glitchy aren't they? Have to say, I checked my cables when I stripped the valve down (5 times. Aaargh) and they seemed fine, but one must have been slowly fraying. What really pissed me off was every time I stripped and looked at it, I couldn't see anything wrong. With 33k on the clocks, the cables will be pretty young, so maybe it's not them.

so, the other thing to check is whether the end plate is slightly bent so when you do it up it seems ok, but when you bolt the cover back on, it nips the valve up. That was the first problem I had when I bought the current set of downpipes.

I read your post with interest as I have been sorting out the EXUP valve on my 2003 1000. Everything was fine when I tested it last night after a swap out with a used valve from EBay. This morning I pinched all the bolts up and put the cover on. Went off to play in the sun this afternoon and immediately the rev counter was showing the usual 0 - 7k message. Back home I found that the cam retaining bolt was pinching against the cover and stopping the valve moving. Transpires that the cam retaining bolt head that came with 'new' valve was about 5mm deep against the 3mm or so for the original. Swapped them over and alls well. I also used just one washer instead of the two that came with the valve

One other thought - have you checked and cleaned all the electrical connectors in the servo motor circuit? Hope you get it sorted - good luck. Nick.

I've fixed the bugger! there was a lip on the casting and groves worn on exup valve where the two had rubbing next to each other during operation.i filed the casting smooth with a smooth file and emery clothed the end of the exup valve where it meets the casting,applied copperslip and have riden it for 100 miles or so with no reaccurance of the 7k fault.the valve was sticking open due to the wear on the casting.Hope this helps someone at some point!

Had a similiar problem which was doing my head in, I had the valve out for the umpteen time and noticed a strand on the cable cracked near the outer cover end on the pull cable, replaced the cables and all is well. Still cannot figure how it could have happened as I always removed the cable with my bare fingers and they are not sharp enough to snap a stainless steel strand. WeMoto to the rescue

I'm a bit old skool as far as exhaust systems go, only ever used to tuning British 4 stroke twins and rule of thumb was always providing the top end had the right ammount of fuel and air get rid of it via the exhaust as quick as possible ( it was said 11 inches of pipe from the exhaust port was the optimum length ). So why on earth have this chunk of casting blocking your escaping gas ? My Gen 1 1000 has been Ivanised and such was the state of my exup system apart from the servo and the outer cables, the rest completly unserviceable that i have removed it. Contary to many comments made and possibly about to be made it has made no difference in my opinion, the engine performs outstandingly.

Old Brit twins with 2 valves per head revved to 6k rpm or thereabouts, no?

Yamaha's 5-valve head Genesis-era motors go almost double that and there's a massive difference in gas flow characteristics at such high rpm. Tuning the exhaust to deliver optimum performance at 11,500 rpm - taking into account valve overlap, gas velocity, resonance, scavenging etc - means that there would inevitably be a compromise in header length, collector box/manifold design and so on without something like an EXUP valve.

The EXUP valve isn't blocking the gas flow above 6k rpm but below that the valve rotates into the gas flow to alter the resonance and scavenging characteristics of the system. The 11" header rule was fine for Brit twins because they operated in a relatively narrow rev range. The EXUP in effect provides a variable length header to provide good exhaust performance across a 10k rpm range.

Most who have removed or disabled the EXUP do notice a detrimental effect on low-mid range performance, irrespective of any jetting changes. You're fortunate in that you aren't able to discern any loss.

Most who have removed or disabled the EXUP do notice a detrimental effect on low-mid range performance, irrespective of any jetting changes. You're fortunate in that you aren't able to discern any loss.

No, the bike has'nt experienced any loss, i as the rider am able voice that experience and still maintain that re jetting the carbs and providing the correct air intake counteracts that over expensive mechanical abortion slung in our exhaust system.

So everyone riding Gen 1 Fazers have entered the WSB now... no seriously Falcon thanks for the technical info and your opinions on the pro's of exup. But I'm well into my 6th decade now and maybe, maybe my perceptions and reactions are not as fine tuned as they used to be which could be why i felt no benefit in keeping a well worn exup set up or having it removed.

chill out man i dont think falcon said everyone who rides fazers has entered wsb or anythink like, and so what if hes a knowledgeable bloke.maybe if you had your non ex-up fazer dyno-ed and published the results then we could benifit from your wisdom

with a perfect engine we would have fully variable intake trumpet length, cylinder compression, intake valve timing, exhaust valve timing and exhaust length. An engine is a mechanical pump really and as we can't adjust many of those attributes the engineers have to optimise for a specific operating characteristic.

What we can do is alter some of those parameters though , like honda with opening a second set of intake vales (vtech) , benelli with the intake trumpet change (lifts the 'cone' of the top) and putting valves in the exhaust to alter the back pressure.

I do look forward to the day when we have pneumatic valves, forced induction (turbos will return!) and variable exhaust capability to give us a motor able to operate at it's most efficient capability over a wide rev range.

Right now bikes are built as leisure devices and the requirements for fuel economy are secondary to power and basic marketing requirements. In 20 years i think we'll be riding smaller (400cc?) engines yet generating more power and we'll go fully automatic, we'll have a gear shifter and clutch - just they won't physically do anything as the computer will control the gear control as i think we might have more gears to allow the engine to remain in a specific rev range for efficiency requirements.

with a perfect engine we would have fully variable intake trumpet length, cylinder compression, intake valve timing, exhaust valve timing and exhaust length. An engine is a mechanical pump really and as we can't adjust many of those attributes the engineers have to optimise for a specific operating characteristic.

What we can do is alter some of those parameters though , like honda with opening a second set of intake vales (vtech) , benelli with the intake trumpet change (lifts the 'cone' of the top) and putting valves in the exhaust to alter the back pressure.

I do look forward to the day when we have pneumatic valves, forced induction (turbos will return!) and variable exhaust capability to give us a motor able to operate at it's most efficient capability over a wide rev range.

Right now bikes are built as leisure devices and the requirements for fuel economy are secondary to power and basic marketing requirements. In 20 years i think we'll be riding smaller (400cc?) engines yet generating more power and we'll go fully automatic, we'll have a gear shifter and clutch - just they won't physically do anything as the computer will control the gear control as i think we might have more gears to allow the engine to remain in a specific rev range for efficiency requirements.

Right now bikes are built as leisure devices and the requirements for fuel economy are secondary to power and basic marketing requirements. In 20 years i think we'll be riding smaller (400cc?) engines yet generating more power and we'll go fully automatic, we'll have a gear shifter and clutch - just they won't physically do anything as the computer will control the gear control as i think we might have more gears to allow the engine to remain in a specific rev range for efficiency requirements.

Brilliant I'll be in my 90's then much lighter bikes less physical movement to be able ride but to still able to bend the hands on the rev counter/ speedo, magic. Hopefully exup will be long gone by then so that i dont have bend over to remove it..........

Hmmm , I wonder if he will return to you in a months time for the Quick 8 minute exup valve service now that its functioning OK ? Sounds to me as there is probably a lot of Gen 1s out there bogging around out there with seized or semi seized valves ........ and if thats the case all the moving parts are well worn by now and all the Copper grease in the world aint going to replace that worn metal. Bin the Bitch.

Hmmm , I wonder if he will return to you in a months time for the Quick 8 minute exup valve service now that its functioning OK ? Sounds to me as there is probably a lot of Gen 1s out there bogging around out there with seized or semi seized valves ........ and if thats the case all the moving parts are well worn by now and all the Copper grease in the world aint going to replace that worn metal. Bin the Bitch.

1. I doubt if he will return in a month for a service of the Exup. I say that because we did it properly and that means it will not need attention until the next service interval and then it will need around 20 mins to put right for another interval. It should be a service item but is not on the Yamaha service schedule so often does not get attended to. We do choose to treat it as a service item as to not do so is just asking for trouble later.

2. I feel that your comments around seized and semi seized valves having well worn parts is, frankly, preposterous. How will a seized part wear? It is the friction between two badly lubricated moving parts that causes wear - once the valve is seized, the wear stops. Or am I being stupid here? The lack of wear on my now departed 100,000 miler would tend to support what I say.

Anyway, you clearly have your mind made up about the justification of your decision and no amount of logic, evidence and/or reason is going to change it.

Have to say since I just fixed my EXUP, it has made a significant difference from tickover up. Without an EXUP working properly it's like riding a more modern bike with stuck on the 'Rain' map. Very fluffy and unresponsive at low revs

I might be wrong here, but I think that there's two issues. First, you've got the valve not opening properly, but also, the ignition map is altered if it's stuck.

If you've only ridden with the EXUP stuck, then getting rid of it altogether is an improvement because the ignition is not fully advanced unless the EXUP works. But an Ivanised Fazer with a fully functioning EXUP gives a Fazer the best torque curve possible and does smooth and enhance low rev power. I'm not talking ultimate bhp here but low rev performance, and there are dyno graphs to prove it

The full systems, Akra, Holeshot and Yoshi, do not perform as well as the stock headers. I know it's not much of a difference and binning the system doesn't lose that much, but it's a difference you can feel.

I totally understand if you want to bin from the hassle factor alone though.